In my Mini-Rat case mod, I've tired out some of this Iron Paint I bought at the hardware store:
It allows you to get a rust effect on almost any surface. I used it to make some plexi look like rusted steel. It requires two coats of the paint, half an hour apart, then after an hour you can spray on the Rust Activator.
I'm using the Linux Box for this guide and also as an experiment. It is supposed to keep rusting over time and starts rusting after about an hour. So I'm going to take a few photos over the next few days to see how much it keeps rusting
This is the case I'm using for the test before the paint goes on. The front is all Bondo:
Here's the case with a coat of the Iron Paint. I only did one coat for this experiment, unlike the two coats recommended, just to see what happens.
After about an hour:
As you can see there is rust forming, but it's fairly light coloured.
After I took that picture I sprayed on a little more Rust Activator in some dry looking spots and have left it to go. I'll take a few more pictures tonight and then over the next few days.
That should give anyone who would like to use this for a case mod, get an idea on how the rust may end up looking if it doesn't seem right straight away.
So, sit back and instead of watching grass grow on a Chia Pet, I'm watching rust form on a case!